Types of messages used to establish connections within a transport network have often been standardized for the purposes of enabling interoperability between equipment of diverse origins, between the different management domains, or between different operators. Thus, the standards organization IETF regularly publishes RFCs (Request for comments) regarding the standardization of signaling for establishing connections within a transport network. Many types of transport networks are known. For example, among known transport networks are those using layer-1 switching like TDM, WDM or Lambda or wavelength bands, or Fiber or physical Ethernet ports or other layer-1 protocols; layer-2 switching like Ethernet frame switching, ATM, Frame Relay or other layer-2 protocols; and layer-3 switching like IP packet switching, IP/MPLS labeled packet switching, or other layer-3 protocols. As an additional example, one may also refer to GMPLS (Generalized Multiprotocol Label Switching) architecture, to RFCs 3471 and 3472, and also to RFC 3473 regarding the RSVP-TE (for Resource Reservation Protocol—Traffic Engineering) protocol.